Eye movements of monkeys during discrimination learning: Role of visual scanning.

In Exps I and II with 7 stumptailed monkeys (Macaca arctoides), Ss were given a series of 2-choice, dot-pattern discrimination reversal problems. Results indicate that the rate of reversal learning was markedly retarded by the experimental condition. The magnitude of the effect was unrelated to the similarity of the uninformative stimulus to the discriminative stimuli. In Exp III, 5 experienced Ss were given a series of discrimination problems without reversals, during half of which the experimental condition was in effect. The results were similar to those of the 1st 2 experiments. In Exp IV (3 experienced Ss), each trial began with uninformative stimuli, which were replaced by the discriminative stimuli when visual scanning occurred. The uninformative stimuli had no clear-cut effect on discrimination learning. Findings indicate that the information provided by above-minimum levels of scanning is not necessary for discrimination learning per se, but it does appear necessary for efficent discrimination learning. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congruity theory and linear models of attitude change.

Evaluated C. E. Osgood and P. H. Tannenbaum's (see record 1955-08361-001) congruity model of attitude change, a regression model derived from the Osgood and Tannenbaum model, and D. R. Heise's (see record 1969-08323-001) 3 general linear models of attitude change, using data obtained from 208 undergraduates. 104 Ss rated 8 3-word (subject, verb, object) sentences 1st, and then rated the individual words. The other Ss rated the individual words 1st. The mean ratings for the 2 groups were compared to obtain the attitude change for each element, and the models were used to predict the change which resulted from the combination of the words into a sentence. Sex differences were found in mean attitudinal evaluations, and the inclusion of higher-order interaction terms increased the predictability of attitude ratings for females more than for males. Heise's Model III was the best predictor of attitude change, followed by his Model II and the regression model derived from the Osgood and Tannenbaum model. The Osgood and Tannenbaum model gave poor prediction of the mean attitudinal changes obtained. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apoptosis in interface membranes of aseptically loose total hip arthroplasty

The terminal events leading to periprosthetic osteolysis are multifactorial in nature and modulation of this process after the stage of osteolytic mediator release has been futile. Recently, the demonstration of the ability of bisphosphonates to inhibit bone resorption that is mediated by particle-stimulated macrophages and their induction of osteoclast apoptosis suggests a potent area for modulation of osteolysis at the prosthesis-bone interface. The purpose of this study was to determine the mode of cell death that occurs at the osteolytic interface of failed total hip arthroplasty (THA). TUNEL staining, DNA laddering, and immunodetection of poly(ADP-ribose)polymerase (PARP) protein were used to identify the presence of apoptosis in interface membranes from 25 patients aged 28–88 years old (mean, 58 years) harvested at the time of hip revision surgery. Our results demonstrated positive TUNEL stain in 100% of specimens with an average 37% of cells (range 12–60%) positively stained for TUNEL whereas less than 8% of control tissue cells showed positive staining. DNA laddering, a characteristic feature of apoptotic cells, was observed in 82% (28/34) of specimens studied at both the acetabular and femoral side of aseptically loose THAs. No laddering was observed in control tissues. Finally, using Western blot analysis, we observed the appearance of the 89 kDa PARP fragment associated with apoptosis in 92% of specimens (30/33). Our results demonstrate the presence of apoptotic cell death in interface membranes of THAs suggesting that apoptosis-related events are indeed associated with periprosthetic osteolysis and could serve as a specific target point for therapeutic modulation. © 2001 Kluwer Academic Publishers     

Analysis of a modified variable-length tuning post in a rectangular waveguide.

A modified variable-length post for use in high power waveguide tuning networks is analyzed to determine its reactance properties. Theoretical predictions are shown to be in good agreement with experimental results. An investigation of the reactance characteristics and the aperture voltage characteristics of the modified post, as a function of its dimensions, is also reported.     

Synchronous Control of a Static AC Induction Motor Drive

Conventional methods of controlling an induction motor utilize regulation of stator current and motor slip frequency in order to maintain system stability. This control strategy requires a shaft speed feedback and fast-response current regulation. An alternative method of controlling an induction motor is presented which achieves the necessary system stabilization by controlling only the motor frequency. The control inherently regulates the motor torque angle by properly adjusting the phase of the converter firing signals. By synchronizing the inverter firing pulses to the motor back electromotive force (EMF) possible adverse inverter operating modes are avoided. The concept of synchronous control eliminates the preprogrammed functional relations previously required and allows the control to adapt to any desired motor flux level. Any desired outer regulating loop can be incorporated to form a fast-response wide-range ac drive system.     

Scale-up of lithium rechargeable batteries

Small-size lithium rechargeable cells in an envelope format were reported at the 20th International Power Sources Symposium [1,2]. This design offers the possibility of making cells using much lighter packing than cells with metal cans. The prismatic format allows good packing in rectangular boxes. Hence they offer the potential for high gravimetric and volumetric energy densities. The cells have now been developed to a size sufficient to form components of a large battery, built to power Army man-portable equipment. Lithium-ion cells have been manufactured using lithium cobalt oxide cathodes and other cathode materials are under investigation. Individual cells up to the 3 A h size have been successfully cycled, with further development possible. A 24 V battery has been constructed and its performance and prospects are described.     

Evolutionary learning of dynamic probabilistic models with large time lags

In this paper, we explore the automatic explanation of multivariate time series (MTS) through learning dynamic Bayesian networks (DBNs). We have developed an evolutionary algorithm which exploits certain characteristics of MTS in order to generate good networks as quickly as possible. We compare this algorithm to other standard learning algorithms that have traditionally been used for static Bayesian networks but are adapted for DBNs in this paper. These are extensively tested on both synthetic and real-world MTS for various aspects of efficiency and accuracy. By proposing a simple representation scheme, an efficient learning methodology, and several useful heuristics, we have found that the proposed method is more efficient for learning DBNs from MTS with large time lags, especially in time-demanding situations. © 2001 John Wiley & Sons, Inc.     

Detection of Pinosylvins in Solid Wood of Scots Pine Using Fourier Transform Raman and Infrared Spectroscopy

Abstract

Diffuse reflectance Fourier transform infrared (DRIFT) and near infrared (NIR) FT-Raman spectroscopy were used to detect pinosylvins in the wood of Pinus sylvestris L. trees. NIR FT-Raman spectroscopy offered the possibility of revealing pinosylvins simply by visual inspection of Raman spectra whereas DRIFT spectra needed a more complicated evaluation. Pinosylvin and resin acids from Scots pine were examined as to the possibility of their being the cause of observed spectral differences between sapwood and heartwood. Since pinosylvins are important compounds for the decay resistance of Scots pine wood, the detection of pinosylvins with Raman spectroscopy might be used to assess durability of wood products.     

Computer-mediated communication in adolescents with and without a history of specific language impairment (SLI)

The various uses of computer-mediated communication (CMC) are transforming the nature of social interactions and human relations among adolescents. Little is known about engagement of exceptional youth with this technology. The present study investigated the implications of language and social factors for frequency of CMC use and its relationship to adolescent well-being in young people with and without a history of specific language impairment (SLI). Eighty six adolescents with a history of SLI and 90 typically developing 17 year olds participated. Participants completed standardized assessments of psycholinguistic abilities and self-report measures of language motivations and social motivations for CMC use, as well as anxiety and depression. Results indicate that language abilities have a complex relationship with frequency of CMC use; social abilities have a more direct association and are predictive of frequency of CMC use. Both adolescents with SLI and typically developing adolescents were less shy online. No association was obtained between frequency of CMC use and reported emotional symptoms of anxiety and/or depression. It is argued that the characteristics of CMC, in terms of its less stringent language demands and its reduced-cues environment, can provide a medium for positive adaptation of adolescents with communication challenges.     

How To Reduce Risks With ActiveX

In August, a group of 20 security experts convened at a workshop funded by the Center of Internet Security Expertise, a US Department of Defense funded body, to discuss the vulnerabilities in Microsoft's ActiveX.